bypass tankless in smith water boiler

I've read several different opinions on capping off the tankless coil. I don't want to run in series with the tankless on my smith series 8 boiler. just bypass it with an electric water heater.
we have extremely low electric rates

There is a 4007a Aquastat that the thermostat splices into then runs to a carlin 40200-02. I really don't understand about the aquastat the manual says it is low limit. but there is no high limit that i can see but i have 2 more boilers (3 family house) that uses the same setup. Do i set the temp at 140 or 190?

I do know most of the workings of the boiler just not the aquastat. plus information on capping the coil. not removing it. Thank you very much